Engineering sensitive gas sensor based on MOF-derived hollow metal-oxide semiconductor heterostructures.

Metal-organic frameworks (MOFs) derived hollow heterostructured metal oxide semiconductors (MOSs) are a class of functional porous materials exhibiting distinctive physiochemical properties. Owing to the unique advantages, including large specific surface, high intrinsic catalytic performance, abundant channels for facilitating electron transfer and mass transport, and strong synergistic effect between different components, MOF-derived hollow MOSs heterostructures can work as promising candidates for gas sensing, which have thus attracted increasing attention. Aiming to provide a deep understanding on the design strategy and MOSs heterostructure, this review presents a comprehensive overview on the advantages and applications of MOF-derived hollow MOSs heterostructures when they used n for the detection of toxic gases. In addition, a deep discussion about the perspective and challenge of this interesting field is also well organized, hoping to provide guidance for the future design and development of more accurate gas sensors.

Dimension Engineering in Noble-Metal-Based Electrocatalysts for Water Splitting.

Dimension engineering plays a critical role in determining the electrocatalytic performance of catalysts towards water electrolysis since it is highly sensitive to the surface and interface properties. Bearing these considerations into mind, intensive efforts have been devoted to the rational dimension design and engineering, and many advanced nanocatalysts with multidimensions have been successfully fabricated. Aiming to provide more guidance for the fabrication of highly efficient noble-metal-based electrocatalysts, this review has focused on the recent progress in dimension engineering of noble-metal-based electrocatalysts towards water splitting, including the advanced engineering strategies, the application of noble-metal-based electrocatalysts with distinctive geometric structure from 0D to 1D, 2D, 3D, and multidimensions. In addition, the perspective insights and challenges of the dimension engineering in the noble-metal-based electrocatalysts is also systematically discussed.

Electrochemical quercetin sensor based on a nanocomposite consisting of magnetized reduced graphene oxide, silver nanoparticles and a molecularly imprinted polymer on a screen-printed electrode.

An electrochemical quercetin (QR) sensor is described that is based on the use of magnetic reduced graphene oxide (MrGO) incorporated into a molecularly imprinted polymer (MIP) on the surface of a screen-printed electrode (SPE). The MrGO consists of reduced graphene oxide (rGO), magnetite (Fe3O4) and silver nanoparticles (Ag). The analyte (QR) is electrostatically adsorbed on the surface of the MrGO. Finally, the MIP was deposited via in-situ polymerization. The composite was characterized by X-ray diffraction, Fourier transform infrared spectroscopy and Vibrating sample magnetometry. The morphologies and electrochemical properties of different electrodes were characterized by Field emission scanning electron microscopy, Electrochemical impedance spectroscopy and differential pulse voltammetry. Under optimal conditions, the modified electrode has a linear response in the 20 nM to 250 µM QR concentration range. The limit of detection is 13 nM (at an S/N ratio of 3). The electrode is selective, stable, regenerable and reliable. It was applied to the determination of QR in spiked pharmaceutical samples and gave satisfactory results. Graphical abstract Schematic presentation of a method for sensing quercetin. It is based on the use of screen printed electrode modified with magnetized reduced graphene oxide and a molecularly imprinted polymer.

Screening and determinations of tissue polypeptide antigen by label-free optical immunosensing method.

Based on the specificity of the immunoreaction of anti-body and antigen, and the resulting localized surface plasmon resonance extinction response of functionalized nano-Au monolayer on glass chip, a novel label-free optical immunosensor with amplified sensitivity has been developed for the detection of tissue polypeptide antigen (TPA). The nano-Au monolayer on glass chip was controllably prepared using 3-mercaptopropyltrimethoxysilane (MPTMOS) as linker by a solution self-assembly method. To analyze its quality, the nano-Au monolayer was characterized by UV-visible spectrum and atomic force microscopy (AFM). The resulting chip was modified by tissue polypeptide antigen antibody (anti-TPA), and then bovine serum albumin (BSA) was employed to block the possible remaining active sites of the nano-Au monolayer. An immunosensor was constructed with biocompatible monolayer nano-Au membrane and the desirable TPA antibody/BSA composite membrane, and it showed good selectivity, high sensitivity and a wide linear response to TPA in the range of 1-1000 ng L(-1) with a detection limit of 1.2 x 10(-3) ng L(-1), as well as good stability and long-term life. Owing to its ease of operation, low detection limit and low cost, it is expected that the proposed procedure may hold great promise in both research-based and clinical assays.